1. Field of the Invention
The present invention relates to an optical switch used in, for example, an optical network of a high-density light wavelength multiplex system and to a method of controlling the same and, more particularly, to a compact multifunctional optical switch and a method of controlling the same.
2. Description of the Related Art
In recent years, with rapid spread of the internet or the like, a communication transmitting system is shifting to a system using an optical fiber. Further, with an object of higher density formation of transmission capacity, there is being adopted a WDM (Wavelength Division Multiplexing transmission system using optical multiplexing conversion. In order to adopt the WDM system, an optical control communication module for synthesizing/dividing, switching, or attenuating optical signals having different wavelengths becomes indispensable.
As conventional examples of an optical switch for switching light, there are technologies disclosed in, for example, Japanese Patent Laid-Open No.301812/1992 and Japanese Patent Laid-open No.264415/1992. The former optical switch is constructed by a constitution in which waveguides are formed in a shape of a lattice, slits are provided at intersections of the waveguides, mercury, silicone and air are movably interposed at the slits and mercury or silicone interposed at the waveguides are switched by heating these to move to thereby control light. The latter switch is constructed by a constitution in which communicating tubes are provided at intersections of waveguides, a liquid is filled (sealed) in the communicating tubes while constituting gaps and sizes of the gaps are adjusted by heating the liquid and vaporizing portions thereof to thereby control light.
However, according to the above-described two optical switches, the waveguides, the slits and the gaps must be formed (arranged) accurately. Furthermore, mercury or the like or the liquid must be sealed. Accordingly, there poses a problem that fabrication of the optical switches is difficult.
Further, the temperature of mercury or the like or the liquid needs to be controlled accurately and, accordingly, the size of supplementary mechanisms other than the main body of the optical switch, such as heating mechanism, a temperature sensor and a control mechanism thereof, become large. Furthermore, the number of parts is also increased. That is, the optical switch cannot be made compact, and fabrication thereof is complicated.
It is an object of the invention to provide an optical switch which is compact and has high productivity and to provide a method of controlling the optical switch.
In order to resolve the above-described problems, an optical switch according to the invention characterized in comprising an input section for inputting a light beam, optical parts each having an optical path changing characteristic movable to a position of blocking the light beam of specially selected wavelength outputted from the input section, output sections provided respectively in correspondence with a case in which the optical path is not changed by the optical parts, driving means for separately driving the optical parts, and driving control means for controlling to arrange the optical parts via the driving means and selecting the output sections constituting output destinations of the light beam. The optical switch can be made compact since a temperature sensor or the like is not. Furthermore, productivity is increased since there is not a member which needs fine fabricating steps as in a conventional member such as a waveguide or the like.
Here, there may be constructed a constitution comprising a plurality of the optical parts in a series direction relative to the light beam and comprising the output sections in correspondence with respectives of the optical parts, and there may be constructed a constitution comprising a plurality of the input sections in a parallel direction and comprising the optical parts in correspondence with respectives of the light beams of specially selected wavelength from the input sections.
As a most general constitution, there is exemplified a constitution comprising two of the input sections in a parallel direction, comprising two of the output sections in the parallel direction at positions opposed to the input sections and comprising two of the optical parts for determining the output destinations of the light beams of specially selected wavelength for the respective light beams. In the case of constructing the constitution, a further large-scaled optical switch can be constituted by connecting a plurality of the optical switches, for example, in a shape of a matrix.
Further, in the case of providing a plurality of the driving means, although it is necessary to widen an interval between the optical parts such that front and rear ones of the optical parts and the driving means do not interfere with each other, when the front and rear ones of the driving means relative to the light beam are arranged in a zigzag shape between the same optical parts, the interval between the optical parts can be narrowed. That is, the optical switch can be made further compact.
In this case, when there is constructed a constitution in which the moving optical members integrating the driving means to the optical parts are arranged in a zigzag shape such that the driving means are disposed between the same optical parts interposing the light beam, the productivity in assembling is promoted.
Further, as the driving means, for example, there is used a piezoelectric actuator. In this case, when there is constructed a constitution comprising a piezoelectric body producing an elongating and contracting oscillation and a moving body frictionally driven by the elongating and contracting oscillation produced to the piezoelectric body, the optical switch can further be made compact since there is constituted the driving means which is compact and having high torque More specifically, there is used a piezoelectric actuator of a rotational type or a linear type.
Further, when the driving means is a piezoelectric actuator, the following constitution can be constructed.
First, the control means may be constructed by a constitution of inputting a preparatory signal before driving operation. In this case, the piezoelectric actuator is warmed up by the preparatory signal to thereby improve response performance and accordingly, the response of the optical switch can be promoted.
Further, when the control means is constructed by a constitution having a self-excited oscillating circuit, the piezoelectric actuator can be driven more efficiently.
Further, when there is provided a support member for movably supporting the optical part and the control means is provided to the support member, a space is effectively utilized and the optical switch can further be made compact.
Further, in the above-described optical switch, when the plurality of optical parts are controlled to drive simultaneously, a time period necessary for switching the optical parts can be shortened. That is, the response of an optical communication apparatus is enhanced.